the rectangule piece should be 10cm long x about 4cm wide. The "L" shape is 10cm (from corner to tip) on the outside & 4.5cm on the inside X 3cm wide. Those are the measurements for the child's size. If you add a couple of cm to the lengths it could end up adult size (I'll play around with it a bit to get better measurements)
Also to fit rabbit ears you could cut holes it the top, but I haven't tried that yet.
you will need: material/cotton interfacing (I find iron on interfacing best) scissors thread needle
Method: attach material to interfacing Cut 1 of each piece of pattern
fold rectangle in half, sew along one side from fold down to end
pin end of seam to middle of shawl piece (the one that looks like an "L" shape) sew pieces together
iron on interfacing will keep to material from fraying